The 2019 Washington Nationals season was the Nationals' 15th season competing as the Major League Baseball (MLB) franchise representative in the District of Columbia, the 12th season at Nationals Park, and the 51st since the original team was started in Montreal, Quebec, Canada. The team clinched a playoff berth for the third time in four seasons on September 24. The Nationals won their first ever National League pennant on October 15, and eventually won their first World Series in franchise history on October 30, becoming the seventh Wild Card team to win the World Series. The Nationals also set all-time franchise records in home runs (231) and runs scored (873).

Nationals Park is a baseball stadium along the Anacostia River in the Navy Yard neighborhood of Washington, D.C. It is the ballpark of Major League Baseball's Washington Nationals. Since its completion in 2008, it was the first LEED-certified green major professional sports stadium in the United States.